Q1 and Q2 connected as BJT common base amplifiers , while Q3 and Q4 with common emitter . Their common connection (Q3 and Q4 collectors) will have same aplitude as on amplifier output, but to drive output load Q6 Q7 and Q8 are put .
Q5 together with thermocompensation diodes (they also give fixed voltage to Q5 base and define current together with 330 Ohm resistor connected to Q5's emitter) forms current source for Q6's output.
2 diodes connected to Q7 and Q8 are using for biasing them , and define amplifier class (A, AB).
Amplifier has 1 negative feedback defining gain (100 k and 10k resistors) as 100k/10k = 10.
And also correcting capasitor 20 pf and 100 pf provide gain decrease at high freq and stability improvement for opamp and amplifier whole.
100 Oh resistors on Q7 and Q8 emitters , provide curreent protection for output short circuit .